1. Field of the Invention
This invention relates to the art of balancing universal joint shaft assemblies and particularly deals with the mounting of balancing weights in C-shaped rings carried by universal joint components and deforming the rings to lock the weights in balancing positions.
2. Prior Art
German utility model Pat. No. 1,746,291 dated Apr. 8, 1957 issued to the assignee of this application discloses a universal joint having an annular groove of dove-tail cross section receiving wedge-shaped weights pressed against the inner walls of the grooves by a set screw between adjoining halves of the weights. This arrangement requires a high concentration of material to accommodate the annular groove without unduly weakening the assembly. Such concentration of material is not available in small and medium sized universal shaft assemblies. Therefore, in such assemblies it has been necessary to determine the dynamic unbalance on a balancing machine and compensate the unbalance at least approximately by weights in the form of metal strips spot welded near the joints. In many cases, however, for reasons of deficiency of available space or owing to excessive unbalances, this is insufficient to insure quiet running of the shafts and balancing could only be obtained by selective removal of material by boring or grinding. These procedures are complicated and time consuming, requiring special balancing machines equipped with devices for welding the balancing weights and/or removing the material. In such cases, after the unbalance has been measured on the balancing machine, the universal shaft has had to be transferred to a work bench or separate device where balancing weights are welded on, after which the shaft is again placed on the balancing machine for a test run following which material is removed if required at another separate operating station. Frequently, additional test runs are necessary.
Furthermore, in nearly all prior art cases, the welding for securing of the balancing weights and the boring for removing material from the universal shaft reduces the strength of the components involved and this disadvantage can only be compensated by providing excessive material in the form of a ring for boring when the components are being constructed or by using thick tubes affording sufficient safety against dangerous accumulation of tension caused, for example, by hardening at the weld spots. The increased provision of material is expensive and increases the inertia moment of the universal joint shaft which may also increase the noise of operation, particularly in Cardan shafts.